title: Distributed Raman amplification using ultra-long fiber laser with a ring cavity: characteristics and sensing application.
abstract: Distributed Raman amplification (DRA) based on ultra-long fiber laser (UL-FL) pumping with a ring cavity is promising for repeaterless transmission and sensing. In this work, the characteristics (including gain, nonlinear impairment and noise figure) for forward and backward pumping of the ring-cavity based DRA scheme are fully investigated. Furthermore, as a typical application of the proposed configuration, ultra-long-distance distributed sensing with Brillouin optical time-domain analysis (BOTDA) over 142.2 km fiber with 5m spatial resolution and ± 1.5 °C temperature uncertainty is achieved, without any repeater. The key point for the significant performance improvement is the system could offer both of uniform gain distribution and considerably suppressed pump-probe relative intensity noise (RIN) transfer, by optimized design of system structure and parameters.
authors.forename: Xin-Hong
authors.initials: XH
authors.lastname: Jia
authors.forename: Yun-Jiang
authors.initials: YJ
authors.lastname: Rao
authors.forename: Zi-Nan
authors.initials: ZN
authors.lastname: Wang
authors.forename: Wei-Li
authors.initials: WL
authors.lastname: Zhang
authors.forename: Cheng-Xu
authors.initials: CX
authors.lastname: Yuan
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Yan
authors.forename: Jin
authors.initials: J
authors.lastname: Li
authors.forename: Han
authors.initials: H
authors.lastname: Wu
authors.forename: Ye-Yu
authors.initials: YY
authors.lastname: Zhu
authors.forename: Fei
authors.initials: F
authors.lastname: Peng